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Wyświetlanie 1-11 z 11
Tytuł:
An integrated approach to estimate storage reliability with masked data from series system
Autorzy:
Zhang, Yongjin
Zhao, Ming
Powiązania:
https://bibliotekanauki.pl/articles/27322965.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
storage reliability
masked data
EM-LS algorithm
series system
LS method
Opis:
Storage reliability is of importance for the products that largely stay in storage in their total life-cycle such as warning systems for harmful radiation detection, and many kinds of defense systems, etc. Usually, the field-testing data can be available, but the failure causes for a series system cannot be always known because of the masked information. In this paper, the storage reliability model with possibly initial failures is studied on the statistical analysis method when the masked data are considered. To optimize the use of the masked survival data from storage systems, a technique based on the least squares (LS) method with an EM-like algorithm, is proposed for the series system. The parametric estimation procedure based on the LS method is developed by applying the algorithm to update the testing data, and then the LS estimation for the initial reliability and failure rate of the components constituting the series system are investigated. In the case of exponentially distributed storage lifetime, a numerical example is provided to illustrate the method and procedure. The results should be useful for accurately evaluating the production reliability, identifying the production quality, and planning a storage environment.
Źródło:
Eksploatacja i Niezawodność; 2023, 25, 4; art. no. 172922
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
LS-Dyna contact procedure analysis for selected mechanical systems
Autorzy:
Małachowski, J.
Bukala, J.
Damaziak, K.
Tomaszewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/245543.pdf
Data publikacji:
2015
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
contact
finite element method
LS-DYNA
shaft
sleeve
Opis:
Finite Element Method is one of the most frequently used computational schemes in numerical analyses. A contact phenomenon is an essential issue when modelling the physical interaction between two or more bodies. Depending on the used software, the various contact algorithms are applied. In the paper, the authors present the results of evaluation of different contact methods implemented in LS-Dyna CAE software. The most common problem arising during contact modelling is the occurrence of penetration between the coupling elements, which leads to an increase of contact forces and, consequently, a local deformation of finite elements. In the introduction, a theoretical background related to mathematical aspects of contact modelling is presented, in particular search methods for contact surfaces and the penalty forces calculating method. Subsequently, a contact analysis for different variants of interaction of the elements is presented. In the first analysed case, shaft- sleeve interaction, in both rotation and translation, is presented. The variable factors in this case were a number of interacting finite elements and the type of a contact algorithm. The second case focused on the interaction forces resulting from the interaction between two sliding bodies in the harmonic motion. A sliding body was pressed against the plane using an increasing force. A variable factor in this case was the type of the implemented contact algorithm.
Źródło:
Journal of KONES; 2015, 22, 1; 193-202
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical study of dynamic response of reinforced concrete bridge induced by selected heavy vehicle
Autorzy:
Szurgott, P.
Smolarz, M.
Powiązania:
https://bibliotekanauki.pl/articles/244088.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
dynamic test
bridge
vehicle
finite element method
LS-DYNA
Opis:
The main aim of this study is to carry out dynamic simulations of structural response of reinforced concrete bridge loaded with a moving heavy vehicle. Computational dynamics analysis was conducted using LS-DYNA computer code. The selected bridge was a reinforced-concrete structure located on the U.S. 90 in Northwest Florida. The bridge has six prestressed AASHTO type III beams and concrete deck. An 8-axle vehicle including a tractor unit and a low bed trailer were selected as a representative for the study. FE model of the tractor based on previous studies; however, a FE model of the trailer was developed for the present work. Analyses included passages of a vehicle with 47 tonnes cargo. A cargo resting on a trailer was taken into account by changing the material density of selected components in the semi-trailer FE model. Time histories of the bridge deflections in the middle of the span were recorded during the simulation tests. Simulations were performed for the vehicle velocity between 20 and 50 mph, stepped by 5 mph. An influence of the velocity on the bridge deflection was determined. The main objective of the simulation tests on the selected bridge was to assess the actual dynamic load allowance (DLA), also known as impact factor, based on the maximum deflection of the bridge span as a function of the vehicle velocity.
Źródło:
Journal of KONES; 2016, 23, 4; 505-512
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of impact between shunting locomotive and selected road vehicle
Autorzy:
Dziewulski, P.
Stankiewicz, M.
Szurgott, P.
Powiązania:
https://bibliotekanauki.pl/articles/245955.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
finite element method
dynamic analysis
crash test
railway vehicle
LS-DYNA
Opis:
The main aim of this study is to carry out dynamic finite element analysis of a crash between shunting locomotive and selected road vehicle. Numerical simulations include side impact of the running locomotive in the vehicle situated across the track. A considered locomotive based on a popular Polish shunting locomotive – SM42. However, the tested locomotive was slightly modernized in comparison with the original one. Finite element model of the locomotive was developed by the authors whereas the vehicle FE model was download from the free database of such models. FE analysis was carried out according to the PN-EN 15227 standard which provides crashworthiness requirements for railway vehicle bodies. 15 tons large truck was selected as a representative for the study. One of the design collision scenario includes such deformable obstacle for railway vehicles operated on national and regional networks. LS-DYNA computer code was used for the simulations. The paper presents selected results of analysis generally focused on the locomotive frame behaviour. Contours of stress for selected moments of time are presented. Moreover, time histories of selected parameters are depicted. The energy balance was also checked in order to confirm the accuracy of analysis. The current study is a part of the project focused on modernization of the SM42 locomotive. Therefore, it is required to evaluate the locomotive behaviour during the impact test. Dynamic numerical simulation are acceptable since the experimental tests on the complete objects under consideration are impractical and impossible at the moment.
Źródło:
Journal of KONES; 2014, 21, 4; 87-94
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulations of front impact between two shunting locomotives at different velocities
Autorzy:
Szurgott, P.
Kozioł, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/244509.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
finite element method
dynamic analysis
crash test
railway vehicle
LS-DYNA
Opis:
The main aim of this study is to carry out dynamic simulations of a crash between two identical shunting locomotives running at different velocities. Numerical analyses using a Finite Element Method (FEM) include front-end impact of the running locomotive with a stationary one situated on the track. Such collision scenario is required for railway vehicles operated on national and regional networks. A considered locomotive based on a Polish shunting locomotive – SM42, however the tested locomotive was slightly modernized. Finite element model of the locomotive was developed by the authors. FE analyses were conducted according to the PN-EN 15227 standard, which provides crashworthiness requirements for railway vehicle bodies. LS-DYNA computer code was used for the simulations. The paper presents selected results of analyses focused on the locomotive frame behaviour. Simulations were performed for the vehicle between 20 and 90 km/h. An influence of the impact velocity on some output quantities was determined. Contours of effective stress for selected moments of time as well as time histories of selected values are depicted. For modernized locomotives, it is required to evaluate their behaviour during the impact test. Dynamic numerical simulation is acceptable since the experimental tests on the complete objects under consideration are impractical and impossible sometimes.
Źródło:
Journal of KONES; 2016, 23, 2; 381-388
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of the front impact between two shunting locomotives
Autorzy:
Dziewulski, P.
Konarzewski, M.
Szurgott, P.
Powiązania:
https://bibliotekanauki.pl/articles/245458.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
finite element method
dynamic analysis
crash test
railway vehicle
LS-DYNA
Opis:
The main aim of this study is to carry out dynamic finite element analysis of a crash between two identical shunting locomotives. Numerical simulations include front-end impact of the running locomotive with a stationary one situated on the track. The first design collision scenario includes such obstacle for railway vehicles operated on national and regional networks. A considered locomotive based on a popular Polish shunting locomotive – SM42. However, the tested locomotive was slightly modernized in comparison with the original one. Finite element model of the locomotive was developed by the authors. FE analyses were carried out according to the PN-EN 15227 standard, which provides crashworthiness requirements for railway vehicle bodies. LESS-DYNA computer code was used for the simulations. The energy balance was initially checked in order to confirm the accuracy of analysis. The paper presents selected results of analyses focused on the locomotive frame behaviour. Contours of effective stress for selected moments of time are presented. Time histories of selected parameters are also depicted. The current study is a part of the project focused on modernization of the SM42 locomotive. Therefore, it is required to evaluate the locomotive behaviour during the impact test. Dynamic numerical simulation is acceptable since the experimental tests on the complete objects under consideration are impractical and impossible at the moment.
Źródło:
Journal of KONES; 2014, 21, 3; 81-88
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of collision between locomotive and passenger car located on level crossing
Autorzy:
Szurgott, P.
Dziewulski, P.
Powiązania:
https://bibliotekanauki.pl/articles/246815.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
finite element method
dynamic analysis
collision
railway vehicle
passenger car
LS-DYNA
Opis:
The main aim of this study is to carry out dynamic finite element analysis of a collision between shunting locomotive and a passenger car. Numerical simulations include side impact of the running locomotive in the vehicle situated across the track on a level crossing. A considered locomotive based on a popular diesel-electric shunting locomotive SM42 but it was slightly modernized in comparison with the original. Finite element model of the locomotive was developed by the authors whereas the vehicle FE model was download from the National Crashworthiness Analysis Center database and it was dedicated to the crash/impact analyses. FE analysis was carried out according to the PN-EN 15227 standard which provides crashworthiness requirements for railway vehicle bodies. However, additional objective of the analysis was to evaluate the behaviour of a small passenger car during the side impact with about 70-ton locomotive. A subcompact passenger car – Geo Metro – was selected as a representative for the study. One of the design collision scenario impact into low obstacle for railway vehicles operated on national and regional networks. LS-DYNA computer code was used for the simulations. The paper presents selected results of analysis generally focused on the locomotive frame behaviour. Contour of stress for the moment of time is presented. Moreover, time histories of selected parameters are depicted. The energy balance was also checked in order to confirm the accuracy of analysis.
Źródło:
Journal of KONES; 2014, 21, 4; 489-496
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cu-etp copper monotonic tensile test modeling in ls-dyna software using hardening and damage models
Autorzy:
Burak, M.
Pejkowski, Ł.
Skibicki, D.
Stopel, M.
Powiązania:
https://bibliotekanauki.pl/articles/2073649.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
finite element method
strain hardening modeling
damage modeling
LS-DYNA
Cu-ETP copper
Opis:
This paper deals with modeling of monotonic tensile test of Cu-ETP copper in numerical environment using finite element method. The research aims to verify the capabilities of LS-Dyna software in terms of modeling the strain hardening and damage of the material. The numerical analyses were proceeded by experimental tests to determine the materials constants of isotropic hardening model and constant required for modeling of material’s damage. Determined material constants were implemented into LS-Dyna environment using MAT_Damage_3 material model. The specimen model was built using eight-node hexahedrons. Both in case of experimental and numerical tests, the controlled parameter was displacement of the specimen. Obtained strain-stress curves were analyzed and conclusions were drawn.
Źródło:
Journal of Polish CIMEEAC; 2015, 10, 1; 23--28
1231-3998
Pojawia się w:
Journal of Polish CIMEEAC
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of finite element model of shunting locomotive applicable for dynamic analyses
Autorzy:
Dziewulski, P.
Szurgott, P.
Powiązania:
https://bibliotekanauki.pl/articles/247466.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
finite element method
modelling
dynamic analysis
crash test
railway vehicle
LS-DYNA
HyperMesh
Opis:
The main aim of this study is to develop a finite element model of the hybrid-shunting locomotive. Considered locomotive is based on a popular shunting locomotive in Poland – SM42. All components above the locomotive frame could be modified in comparison to the original object, whereas a chassis was essentially unchanged. Such solution allows the operators freely configure components e.g. diesel engine, generator, cooling module, cab etc., according to their own requirements. Works on the FE model were focused on very accurate reflection of the locomotive frame since the planned dynamic analyses include crash tests. FE model of the frame has a fine mesh and it is considered as a deformable component. Other segments of the vehicle are simplified and treated as rigid bodies mostly. FE model was developed on the basis of the locomotive CAD model. It was decided to transform the CAD model of the frame into the FE one applying the midsurface procedure. Such approach is correct since the locomotive frame is made of a large number of steel elements in the form of sheet metal plates and sections welded together. Altair Hyper Mesh software was used in the FE model developing process. Appropriate connections between respective components of the model e.g. wheelset – bogie, bogie – locomotive frame, were applied. Finally, the locomotive FE model consists of about 116 thousands of finite shell and solid elements and about 125 thousands of nodes. Dynamic analyses of the locomotive FE model will be carried out using LS-DYNA computer code.
Źródło:
Journal of KONES; 2014, 21, 4; 95-102
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of Pressure Distribution in Buried Pipes with Liquid in the Explosion
Autorzy:
Parviz, M.
Aminnejad, B.
Fiouz, A. R.
Powiązania:
https://bibliotekanauki.pl/articles/230958.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rura zakopana
metoda Lagrange’a-Eulera
podmuch
ciśnienie
Ls-Dyna
buried pipe
Lagrangian-Eulerian method
blast
pressure
Opis:
In this Paper, a parametric study on pipes buried in soil was performed illustrating the results of blast loading. Effects of various parameters such as the physical properties of water, oil, gas, air, soil, pipes, and TNT have been investigated. The arbitrary Lagrangian-Eulerian (ALE) method was employed using LS-DYNA software. The maximum pressure in a buried pipe explosive was observed at an angle of about 0° to 45° and the minimum pressure occurred at an angle of about 45° to 90°. Therefore, all figures in this study illustrate that fluid pressure levels in buried pipes can help in their stabilization. In generally, by increasing the 1.23 times of liquid density under the explosion, the pressure levels in the soil decreased by 1.3 percent. The gas pressure has been increasing more than oil and water pipes 39.73 and 40.52 percent, respectively.
Źródło:
Archives of Civil Engineering; 2019, 65, 3; 3-14
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical and experimental analyses of a lighting pole in terms of passive safety of 100HE3 class
Autorzy:
Jedliński, Tomasz
Buśkiewicz, Jacek
Fritzkowski, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/2146584.pdf
Data publikacji:
2020
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
passive safety
crash test
EN 12767
finite element method
Ansys LS-DYNA
bezpieczeństwo bierne
test zderzeniowy
metoda elementów skończonych
Opis:
Nowadays trends related to the road safety make the lighting poles producers meet rigorous requirements that decrease the risk of death and injury of vehicle drivers in case of the impact. New requirements are in force from 1 January 2015, when Road and Bridge Research Institute informed that each pole liable to a direct vehicle impact has to meet Standard PN-EN 12767. The article presents the design of a novel, safe lighting pole. The novelty lies in the pole simplicity, which results in the manufacturing technology the cost of which is comparable to that of the conventional pole. Compared to the conventional poles of thickness 3 mm and greater, this one is made of thin-walled steel sheet of increased strength parameters and specially designed sleeve that is fixed to the base plate. The crash tests carried out on the track for the impact experiments proved that the requirements of the standards in the driver highest safety class and in the high vehicle kinetic energy absorption were satisfied both for the speed impact 35 km/h and 100 km/h. The numerical model for simulations of the vehicle behaviour during and after the impact was implemented in software Ansys LS-Dyna. The simplifications of some elements were of negligible influence on the analysed phenomena. The comparative parameters were ASI, THIV and exit velocity of the vehicle. The numerical results were close to the empirical ones, therefore they confirmed that finite element analysis can be successfully applied at the stage of elaborating of the initial concepts of the road lightning poles. It follows that the number of expensive crash tests can be reduced.
Źródło:
Vibrations in Physical Systems; 2020, 31, 3; art. no. 2020307
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-11 z 11

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